docs: def with_subchannel(f,*args):
      "conditionally monitor subchannel"
      def f_with_update(*args):
          try:
              f(*args)
              if monitor_subchannel:
                  update_subchannel_msgs(force=True)
          except AttributeError: #if kc is None
              echo("not connected to IPython", 'Error')
      return f_with_update